Multi-detector row computed tomography (MDCT) allows the acquisition of high-resolution data of the entire thorax. The quality of the data allows the assessment of the bronchi as well as the pulmonary artery tree. Extraction of the pulmonary artery tree is an important pre-processing step, e.g., for embolism detection. Also, in the quantitative assessment of the bronchial tree the accompanying artery tree contains important additional information that can be extracted from MDCT data. Hence, for diagnosis and treatment of asthmatic and emphysematic patients, the simultaneous assessment of the tracheobronchial tree and the accompanying pulmonary artery tree is very important. For example, the ratio of inner bronchial to accompanying arterial diameter is an important parameter in clinical practice in order to detect and quantify airway narrowing and bronchial dilation.
When extracting the pulmonary vessel tree from MDCT data, difficulties may arise when distinguishing pulmonary arteries from veins. For instance, seed-point based region expansion methods for the extraction of the pulmonary arteries suffer from leakage into pulmonary veins.
WO 2006/085254 discloses a method of automatic extraction of a pulmonary artery tree from a 3D medical image, such as multi-slice CT data. In this method, a segmented pulmonary vessel is identified as either an artery or a vein by determining a local measure of arterialness of the vessel. The measure is based on a relation of the orientation of a local bronchus to the orientation of the segmented pulmonary vessel of the local bronchus. When a vessel is identified as a pulmonary artery, it is added to the pulmonary artery tree.
However, the classification of pulmonary arteries and pulmonary veins in the known method sometimes fails.